DESCRIPTION: (Applicant's Description) The overarching goal of this Program Project Grant is to elucidate key aspects of breast development and breast carcinogenesis. The principal research emphasis of the component research programs is a study of the biological function of proteins that play important roles in controlling these processes. The goal of this core is to develop and to make available useful protein expression methodologies that will promote these studies. The work in this core will be divided into two general components. One portion of the work will provide reagents to other investigators in this Program. These services will include the establishment of a bank of approximately 100 key breast genes cloned as full length coding regions and available in all commonly used protein expression vectors (Specific Aim 1). This bank will include genes that are currently known to play a role in yeast development or in the development of breast tumors. In addition, core services will provide normalized cDNA libraries for use in molecular biology, functional, or genetic screens (Specific Aim 2). We also will begin the technology development needed to establish an array of cDNAs in vectors that allow functional testing. The ultimate goal of this work will be to capture all genes expressed in the breast. For the five year period of this grant, our goal will be to isolate 10,000 full length sequences and have them available in vectors that promote functional screens (Specific Aim 3).